Cheuk-Lik Wong, Chun-Kit Fok and Vicki Ho-Kee Tam

Summary

We report a case of elderly Chinese lady with neurofibromatosis type-1 presenting with longstanding palpitation, paroxysmal hypertension and osteoporosis. Biochemical testing showed mild hypercalcaemia with non-suppressed parathyroid hormone level suggestive of primary hyperparathyroidism, and mildly elevated urinary fractionated normetanephrine and plasma-free normetanephrine pointing to a catecholamine-secreting pheochromocytoma/paraganglioma. Further scintigraphic investigation revealed evidence of a solitary parathyroid adenoma causing primary hyperparathyroidism and a left pheochromocytoma. Resection of the parathyroid adenoma and pheochromocytoma resulted in normalization of biochemical abnormalities and hypertension. The rare concurrence of primary hyperparathyroidism and pheochromocytoma in neurofibromatosis type-1 is discussed.

Learning points:

All NF-1 patients who have symptoms suggestive of a pheochromocytoma/paraganglioma (PPGL), even remotely, should undergo biochemical testing.

The initial biochemical tests of choice for PPGL in NF-1 are either plasma-free metanephrines or urinary fractionated metanephrines. Any elevations of metanephrines should be carefully evaluated for the presence of PPGLs in NF-1 patients.

Primary hyperparathyroidism (PHPT) is described in subjects with NF-1. Due to the lack of epidemiological and functional studies, their association is yet to be substantiated. Meanwhile, PHPT may further exacerbate the metabolic bone defect in these patients and should be treated when present according to published guidelines.

Stephanie Teasdale and Elham Reda

Summary

We present two cases of adrenal phaeochromocytoma in patients with a previous diagnosis of neurofibromatosis type 1 (NF1). One had an adrenergic phenotype. The other had a more noradrenergic phenotype. Both had large primary tumours, which increases the likelihood of malignancy. Both also had elevated plasma-free methoxytyramine, which has been linked with malignancy even in non-SDHB phaeochromocytomas.

Learning points

Phaeochromocytoma can have varied clinical presentations.

Methoxytyramine can be useful in the biochemical work-up of both SDHB-positive and SDHB-negative phaeochromocytoma.

The utility of methoxytyramine as a marker of malignancy in NF1-related phaeochromocytoma is unclear, and cases with elevated titres warrant longer follow-up.

Summary

Adrenal cortical carcinoma (ACC) has previously only been reported in eight patients with type 1 neurofibromatosis (NF1). There has not been any clear evidence of a causal association between NF1 gene mutations and adrenocortical malignancy development. We report the case of a 49-year-old female, with no family history of endocrinopathy, who was diagnosed with ACC on the background of NF1, due to a novel germline frame shift mutation (c.5452_5453delAT) in exon 37 of the NF1 gene. A left adrenal mass was detected by ultrasound and characterised by contrast computerised tomography (CT) scan. Biochemical tests showed mild hypercortisolism and androgen excess. A 24-h urinary steroid profile and 18flouro deoxy glucose PET suggested ACC. An open adrenalectomy was performed and histology confirmed ACC. This is the first reported case with DNA analysis, which demonstrated the loss of heterozygosity (LOH) at the NF1 locus in the adrenal cancer, supporting the hypothesis of an involvement of the NF1 gene in the pathogenesis of ACC. LOH analysis of the tumour suggests that the loss of neurofibromin in the adrenal cells may lead to tumour formation.

Learning points

ACC is rare but should be considered in a patient with NF1 and adrenal mass when plasma metanephrines are normal.

Urinary steroid metabolites and PET/CT are helpful in supporting evidence for ACC.

The LOH at the NF1 region of the adrenal tumour supports the role of loss of neurofibromin in the development of ACC.